There is a myth that most people are easy on themselves.
Reality does not support that.
With rare exceptions, people hold themselves to impossible standards. They are cold-blooded prosecutors of their most minor infractions. No statute of limitations is recognized. Stupid or cruel remarks made in elementary or high school can be quickly cited. Their most minor mistakes can be rapidly catalogued and footnoted.
The same people who would urge a friend to get real and put the past in perspective somehow lose all compassion when looking in a mirror.
If you are among this crowd, it is time to abandon those lingering regrets. They get you nowhere and are colossally unfair. You would not judge others that harshly. Stop judging yourself.
A fresh horizon awaits you.